WASHINGTON (AP) — The Senate Intelligence Committee has sent formal requests to more than a dozen organizations, agencies and individuals, asking them to preserve all materials related to the committee's investigation into Russian interference in the 2016 election and related issues, according to a congressional aide. On Thursday, Senate Democrats wrote the White House and law enforcement agencies seeking assurances that they were preserving all materials related to contacts individuals associated with President Donald Trump had with Russians. Congressional staffers have said that they are not aware of any evidence that materials are not being preserved, but Senate Democratic leader Chuck Schumer of New York said Thursday on the Senate floor: There is real concern that some in the administration may try to cover up its ties to Russia by deleting emails, texts and other records that could shine a light on those connections.